Refrigeration



Nov. 4, 1941. H. M; ULLSTRAND 25525135631 REFRIGERAT ION original. Filed June 1i?, 193'/ 2A sneetsbshee; 2

Patented Nov. 4, 1941 UNITED STATES.

PATENT OFFICE Servei, Inc., New York,.N. Y., a

Delaware corporation of Application June rz, ssmserm Nu. 14am Renewed December 8, 1939 Juanma My invention relates to refrigeration, and more particularly concerns cooling ofa storage compartment of a refrigerator. It is an object of my invention to'provide an improvement for cooling -a storagecompartment of a refrigerator'whereby food products may be preserved and maintained at a desired low temperature without dehydration thereof.

Another object of my invention is to increase the effective heat transfer surface of aVVV cooling element in a storage compartment of a refrigerator with the aidof a'heat transfer path or secondary cooling system arranged to provide a maximum amount of usable storage space in the compartment.

A further object of my inventionisv to increase the emciency La/cooling element in a storage compartment of a refrigerator with the /aidofsfheat transfer system having solid shelves, whereby the solid shelves of the heat transfer system may be employed in place of ordinary perforated shelves for storing food products and vat the same time aid the cooling element in maintaining the vdesired low temperature in the compertinent.

' The invention, together with the above and other objects and advantages thereof, will be more fully understoodfrom the following description taken in conjunction with the accompanying drawings forming a part of this specification, and of which Fig. l diagrammatically illustrates a refrigeration system and a side vertical sectional view of a refrigerator embodying the invention; Fig. 2 is a horizontal sectional view of the refrigerator shown in Fig. l and taken on line 2-`- 2 of Fig. 3; andFig. 3 is a vertical sec-- tional view taken on line 3-3 of Fig. 2.

Referring to Fig. 1. Iv have shown my invention embodied in a refrigerator comprising a cabinet i0 having an inner metal shell Ii arranged to be supported within an outer metal shell I2 and'insulated therefrom with any suitable insulating material i4. .The inner metal shell ii defines a thermally insulated storage compartment i5 intowhich access may be had by a door i6 hinged to the front of the cabinet.- Within the storage compartment I5 is arranged a cooling unit or evaporator i1 of a refrigeration system.

The refrigeration system or apparatus I have diagrammatically shown isl of a uniform pressure absorption type, generally as described in Patent No. 2,037,782 to William R. Hainsworth, in which an auxiliary pressure equalizing gas is employed. in a system of this type a refrigerant' fluid, such (ci. ca -fc5) gen, --to produce a refrigerating effect. The rey sulting gas mixture of ammonia and hydrogen flows from cooling unit i1 through conduit i9,

.gas heat exchanger 2 0, and conduit 2| into an vabsorber 22. Y

In absorber 22 ammonia vapor is absorbed by .a suitable. absorbent. such'as water, which enters through a conduit 23. The hydrogen, vwhich is practicallyy insoluble and weak in ammonia,

is returned to the lower part of cooling unit il through conduit 28, gas heat exchanger 20, and

conduit 25; and the enriched absorption liquid is conducted from absorber 22 through a conduit 23, liquid heat exchanger 21, and a conduit 23 into chamber 29 of a generator 30.

By heating generator 30, as by'a gas burner 3i, for example, liquid 'is raised by vapor-lift acztion'through conduit 32 into .the upper part of a ,stand-pipe 33. Liberated ammonia vapor entering stand-pipe 33 from conduit 32, and also'the ammonia vapor expelled from solution in standpipe 83 and chamber 3d, iiows upward into an air-cooled condenser 35. Ammonia vapor is liquefied in 'condenser' and returned to cooling unit il through conduit I8 to complete the refriserating cycle. v

- The weakened absorption liquid from which ammonia has been expelled is conducted from Y A vessel 38 is connected by conduit 39 to the lower part of condenser 35 and by conduit 40 to the gas circuit, as `at absorber 22, for example, so that any hydrogen which may pass into the condenser can flow into the gas circuit. Ammonia vapor not liquefied in condenser 35 flows through conduit 3 3 to displace hydrogen invessel 3B' and force such hydrogen through conduit G0 into the `gas circuit, so that-the total pressure in the system is raised and an adequate condensing pressure is obtained to insure condensation of ammonia vapor in condenser 35.

In order to arrange the cooling unit i1 within Athe storage compartmentl," the rear insulated other parts of the refrigeration system extend through the removable wall section 4 i The cooling unit l1 includes an upper coil 42 and a lower coil 43. The coil 43 may be embedded in or otherwise suitably arranged in heat exchange relation with a shell 44 provided with a plurality of compartments to receive trays for freezing water and the like. The upper coil 42 is arranged with a plurality of cooling ns 45 for'cooling air in the storage compartment l5. Liquid ammonia entering the upper coil 42 through conduit I8 flows downward in counternow to inert gas which flows upward and enters the lower coil 43 through conduit 25. Since the inert gas flows first through the lower coil 43 and'then through the upper coil 42, the gas in the upper coll contains a greater amount of ammonia vapor than the gas in the lower` coil. The partial pressure of ammonia vapor is therefore higher in coil 42 than in coil 43, and evaporation ofliquid ammonia takes place at a higher temperature in the upper coil than-in the lower coil.` In accordance with my invention, inv order to increase the. emiency of the upper coil or cooling element 42 for 'cooling air in the storage compartment, I provide a heat transfer system which is preferably so constructed and arranged that the effective heat abstractlng surface is increased without materially decreasing the usable storage space in the compartment. I accomplish this by providing a heat transfer system including a condensation portion 46, evaporation portions 41, and connecting conduits 48 and 49.

'I'he condensation portion or condenser 46 serves as a part of a heat conductor and is in the form of a looped coil having straight portlons and connecting bends, and is arranged in thermal exchange or heat conductive relation with the upper cooling element 42. The condenser 46 is preferably removably connected to the cooling element 42 and detachable therefrom by providing notches or recesses in the fins 45 to receive the straight portions of the condenser, as shown most clearly in Fig. 3, and rigidly securing the condenser in this position by straps 50 and 5I and connecting bolts 52. 'I'he upper straps 50 bear against the top of condenser 48 and the lower straps 5| bear against the bottom of coil 42, so that the condenser is in good thermal contact with the cooling fins 45.

The evaporationv or heat abstracting portions di of the heat transfer path each comprise a pair oi contacting metallic sheets 53 and 54 having a fluid passage formed therebetween. The top sheets 53 are substantially fiat and connected in any suitable manner, as by welding or brazing, to the bottom sheets 54k. The evaporation portions 41 form solid walls or shelves in the storage compartment and divide the latter into a plurality of separate compartments i5a, I5b, and

Although the solid shelves may be of such size that a space is provided between the edges of the shelves and the vertical walls of the compartment, I prefer to arrange the shelves in such a manner that no flow of air will take place between the separate compartments. To effectively seal the separate compartments from each other, a suitable gasket 55 may be provided about the periphery of each shelf 41, the gaskets being formed of a suitable resilient material, such as rubber, and bearing against the walls of the' inner shell ll at the shelf supports 56. When the door I6 is in its closed position, the inside of the door effectively bears against the portion of the gaskets at the forward edges of the solid shelves. If desired; one or more of the separate compartments may be provided with an independent closure member. Such a separate closure member III. which is hinged at its upper edge to the top shelf 41, is provided at the forward part of the middle compartment lib, as shown in Fig. 1.

The condenser 44, evaporationmembers or solid shelves 41, and connecting conduits 48 and 49 form a closed fluid circuit which contains a suitable volatile fluid that evaporates within the solid shelves 41 and takes up heat thereby transmitting cooling eilect and cooling the separate compartments. The system may be filled with liquid to a point above the top shelf 41,l whereby the shelves constitute evaporation members of the flooded type with the bottom sheets 54 forming chambers for holding the volatile fluid in heat transfer relation to the shelves. The vapor flows upward through conduit 48 into the condenser 46. and me vapory is cooled and Icondensed by the upper cooling element 42. The condensate flows downward through conduit 4'! and back into the solidshelves 41 where it is againl evaporated. In the heat transfer path described, therefore, cooling eect is transmitted by the upper element 42 to the heat transfer system with such system conducting heat therethrough to transmit cooling effect to the shelves 41 which form walls of the smaller compartments.

Since the low temperature cooling element 43 is normally operated below the freezing temperature of water, water vapor is condensed out of therewith. Under these conditions the condensed water vapor freezes and forms a coating l of frost on the low temperature cooling element. Although the shell 44 in which the cooling element 43 is embedded has a limited heat transfer surface which may be employed to assist the higher temperature cooling element 42 for cooling air, the increased heat abstractlng surface provided by the heat transfer path or system makes posible an arrangement for maintaining the separate storage compartments at a higher humidity. This may be effected by insulating the low temperature cooling element 43 with any suitable insulating material 51 to prevent removal of water vapor from air by this cooling element. The insulating material may be pro- :tected with a. sheet metal cover 58 which may be secured to the removable wall section 4|, as shown in Fig. l.

When the low temperature cooling element 43 is insulated and the higher temperature cooling element 42 and heat transfer path are relied upon to maintain the storage compartment at a low temperature, the air is maintained at a higher humidity with less dehydration of the food products stored in the compartment. This is due to the fact that less water vapor is condensed from air flowing in contact with the solid shelves 41 and the higher temperature cooling element 42. When the relative humidity of air in the compartment is below a definite value, no removal of water vapor from air is effected because of the higher operating temperature of the cooling element 42.

Condensation of water vapor is almost una-v voidable when a dew-point higher than 32 F. is

desired. The condensed water vapor may be collected in any suitable manner in the storage compartment, or a drain system may be providaaereei ed for conducting water out of the compartment Any condensate formed on the cooling element 42 and solid shelves 4l may be conducted to a.

common drain conduit which may be arranged to deliver the water to a heat rejecting part of the refrigeration system, such as the generator 80, for example, so that it will be heated and evaporated.

The above described arrangementl for cooling air in the storage compartment is extremely flexible and may be readily modified to maintain the desired temperature and humidity conditions in any of the compartments. Although I prefer to insulate the low temperature cooling element i3 to maintain the upper compartment |a at a humidity which will prevent dehydration of food products stored therein, the cooling element 53 may be employed without insulation when it is desired to maintain the upper compartment at a lower temperature to store certain food products therein.

By providing the solid refrigerated shelves M the middle and lower compartments iSb and Ic may be maintained at a higher humidity, even when the low temperature cooling element 43 is not insulated, so that dehydration of food prody ucts is substantially reduced. Since air inl the skilled in the art that various changes and modifications may be made and that certain features may be employed independently of others, without departing from the spirit and scope of my invention, as pointed out in the following claims.

What is claimed is:

1. In a refrigerator having a thermally insulated storage compartment and structure therein to support food products and the like, an absorption type refrigeration system having first and second cooling elements in which refrigerant fluid evaporates in the presence of an auxiliary agent, said first element being thermally'segregated from said compartment and having a chamber for freezing ice and the like, said refrigerant fluid evaporating into `auxiliary agent at a low temperature in said first cooling element and ata higher temperature in said second cooling element, and a system for heat transfer fluid having a heat rejecting portion in heat conductive relation with said'second cooling element and a heat abstracting portion including said to provide separate storage spaces capable of being maintained at different temperatures. Thus, by increasing or decreasing the size of the middle compartment |5b the temperature of this compartment may be increased or decreased.

In addition to the solid shelves 4l which are arranged to seal and prevent the flow of air from one compartment to another, additional perforated shelves 59 may be provided in the compartment. The solid shelves assist in supporting food products in the different compartments and provide a heat transfer path which does not materially reduce the usable storage space in the refrigerator. When the low temperature cooling element 43 is insulated so that no frost is formed thereon, defrosting of the cooling element is not necessary-and the refrigeration system may be operated continuously under normal operating conditions. Since the heat transfer system is removably connected to the upper cooling element 42, it is insertable into the storage compartment from the front of the cabinet. This removable connection also permits removal of the cooling unit l1 through the opening inthe rear insulated wall when the condenser s6 is disconnected from the upper cooling element also that the heat transfer system may remain in its structural and cooling effect transmission relationship to the compartments of the storage space with removal of cooling unit l1.

Although I have shown and described my invention in connection with a particular type of refrigeration system, I do not wish to be limited thereto since any type of refrigeration system or systems may be employed to provide a low temperature cooling element and a high temperature cooling element in a storage compartment of a refrigerator. It will be understood by those structure so as to minimize the amount of usable storage space occupied by said system in said compartment.

2. In a -refrigerator having a thermally in- -sulated storagecompar'tment and one or more shelves therein to support food products and the like, an absorption type refrigeration system having rst and second cooling elements in which refrigerant uid evaporates in the presence of an auxiliary agent, said first element being thermally segregated from said compartment and having a chamber for freezing ice and the like,

said refrigerant uid evaporating into auxiliary agent at a low temperature in said first cooling element and at a higher temperature in said second cooling element, and a system for heat trans' fer fluid having a heat rejecting portion in heat conductive relation with said second cooling element and a heat abstracting portion in which heat transfer fluid is held in heat transfer relation to said shelf or said shelves so as to minimize the amount of usable storage space occupied by the system in said compartment.

3. In a refrigerator having a thermally insulated storage. compartment provided with an opening, a door for closing the opening. an absorption type refrigeration system having first and second cooling elements in which refrigerant Afiuid evaporates in the presence of an auxiliary agent, said first elementbeing thermally segregated from said compartment and having a chamber for freezing ice and the like, said refrigerant fluid evaporating into auxiliary agent at a low temperature in said first cooling element and at a higher temperature in said second cooling element, and a system for heat transfer fluid constructed and arranged to occupy a minimum amount of usable storage space in said compartment and having a heat rejecting portion and a heat abstracting portion, said system being insertable into said compartment through the opening, and said heat rejecting portieri being in thermal exchange relation with said second cooling element and detachable from such thermal exchange relation.

e. In a refrigerator having a thermally insulated storage compartment and one or -more shelves therein arranged to divide the compartment into a plurality of separate spaces between which flow of air is substantially prevented, an absorption type refrigeration system having first and second cooling elements in which refrigerant fluid evaporates in the presence of an auxiliary agent, said first cooling element being thermally segregated from said compartment and having a chamber for freezing ice and the like, and said second cooling element being arranged to effect cooling of one of the separate spaces, said refrigerant uid evaporating into auxiliary agent at a low'temperature in said first cooling element and at a higher temperature in said second cooling element, and a system for heat transfer fluid including a heat rejecting portionI in thermal exchangerelation with said second cooling element and a heat abstracting portion including a chamber or chambers for holding heat transfer uid in heat transfer relation to said shelf or shelves.

5. In a refrigerator havinga thermally insulated storage compartment and one or more shelves therein to support food products and the like, an absorption type refrigeration system including upper and lower cooling elements connected for upward flow of auxiliary agent in series and downward fiow o'f cooling agent in the presence of the auxiliary agent, said upper cooling element being arranged to extract heat fromv within said compartment and said lower cooling element being thermally segregated from said compartment and having a chamber for freezins ice and the like, andmeans to increase the rate at which heat is extracted from within said compartment by said upper cooling element includa volatile uid in heat transfer relation with said food supporting structure, and a second chamber in heat conductive relation with said second cooling element and connected to said first chamber, said rst and second chambers constitutinl evaporation and condensation portions, respectively, of a circuit for the volatile fluid.

10. In a refrigerator including a cabinet provided with an inner liner member forming a-food storage compartment having an opening at the front of the cabinet, the top and bottom of the liner member being spaced apart substantially the height of the rear and lateral side walls thereof, refrigeration apparatus including a cooling element in said compartment, the. cooling element having a chamber adapted to receive matter to be refrigerated. a door forfthe cabinet opening for inserting and removing food proding a system for heat transfer fluid having a heat rejecting portion in .heat conductive relation with said upper cooling element and a heat abstracting portion in which heat transfer fluid is held" in heat transfer relation to said shelf or shelves,

`whereby the amount of usable storage space occupied by said system-in said compartment is 6. A refrigerator including a cabinet having a thermally insulated storage compartment, refrigeration apparatus having a low temperature cooling element for freezing water and a higher temperature coolingelement for coolingair in said compartment, structure in said storage compartment for supporting food articles and 'the like, a chamber for holding a volatile fluid in heatv transfer relation to said food supporting structure, and aheat transfer' circuit for volatiley ucts and the like into'and'from the food compartment and also affording access to the chamlber of the'cooling element, a shelfin the compartment having the peripheral edges thereof at v or adjacent to the rear and lateral side walls of theliner member and adapted to support food products and the like normally maintained above.' freezing temperature, and meansto vutilize theshelf to abstractA heat frompthe storage com. partment, the last-mentioned means being constructed andv arranged to occupy a minimum amount of usable storage space-and including a rst chamber within the liner member for holding a volatile fluid in heat transfer relation to they ,j shelf, a second chamber/in heat conductive relaf tion with the cooling element, and conduit means connecting the first and' second chamber having a. vertically extending portion adjacent a wall o f the liner member, the first and second chambers constituting evaporation and condensation portions. respectively, of a circuit for the volatile fluid.

l1. Ina refrigerator including a cabinet hav- 'I ing a storage space/and a solid shelf in said space to divide the latter into compartments be- -twecn which circulation of air is restricted, re-

fluid and including said chamber and having a portion in thermal exchange relation -with said higher temperature cooling element.

'1. A refrigerator as set forth in claim 6 in which said chamber forms a fluid e in a shelf, and said shelf divides said` compartment ',into a plurality of separate compartments.

8; A refrigerator as set forth in claim 6 in which said food supporting structure includes a plurality of shelves, each having a chamber forming a fluid passage and dividing said compartment into a plurality of separate compartments substantially without air flow therebetween.

9. In a refrigerator including acabinet having a thermally insulated storage compartment and structure therein for supporting food products and the like, an absorption type.. refrigeration element and at a higher temperature in said second cooling element, a first chamber for yholding said compartments, and said circuit including i system having first and second cooling elements 1 in which refrigerant uid evaporates in the pres-- ence of an auxiliary agent, said first element befrigeration apparatus including a cooling elementA in one ofsaid compartments, food supporting structure in another of said compartments, a first chamber for holding a volatile fluid in heat transfer relation to said food supporting structure, a second chamber detachably connected in heat'conductve relation with said cooling element and connected to said first chamber, said A -first and second chambers constituting evapora*- tion and condensation portions, respectively, ofl

a circuit for the volatile fluid, said cabinet having a common door for gaining access to both of said evaporation and condensation portions being removable as a single unit through said door from said storage space when said second chamber or condensation portion is detached from its heat conductive relation with said coolingelement. 'v

12. A refrigerator including a cabinet having a thermally insulated food storage space provided wfth an inner liner, the food storage space being open at the front of the cabinet, a plurality of horizontally disposed walls in said space forming shelves for supporting food articles and the like, one of the walls dividing the space into compartments between which circulation of air is substantially prevented, thetop, bottom, rear and lateral sides of the liner4` forming walls of the compartments, refrigeration "apparatus includin'g evaporator structure in one of the compartments, the evaporator'structure having a v chamber adapted to receivematter tobe refrigerated, a door for the cabinet opening for in-V serting and removing food products and the like into and from said one compartment and also affording access to the chamber of the evaporator structure, a heat transfer path including a portion in heat transmitting relation to one of the walls of said other compartment and transmitting cooling eiect thereto, and means serving as a heat conductorin heat transmitting relation with said portion for transmitting cooling e'ect thereto, said .heat conductor means'includi'ng ad part in heat conductiverelatlon with the evaporator structure whereby the evaporator structure transmits cooling eect to said heat conductor means when in functioning'relationship, said part of said heat conductor means being detachable from its heat conductive relation with"l the evaporator structure whereby the latter is removable from the cabinet, and said portion and said heat conductor means of the heat transfer path being arranged so that they, may remain in their structural and cooling effect trans.-

`,mission relationship to the other compartment upon removal of the said evaporator structure.

- 13. A refrigerator including a cabinet havingl affording accessto the chamber' of the evaporator structure, a nrst chamber for holding avolatile fluid in heat transfer relation to one'oI the Walls of saidv other compartment, a second cham- Aber connected to said rst chamber,'said irst and second chambers constituting evaporation and condensation portiona'respectively, of a circuit for the volatilel fluid, said second chamber orl condensation portion being vin heat conductive relation with the evaporator structure whereby' i the evaporator structuretransmits cooling effect to said condensation portion when in funcf tioning relationship, said condensation g portion. l or rst chamberbeing detachable from its heat' conductive relation with the evaporator struc- "-ture' whereby the latter is removable from the j cabinet, and said circuit for the volatile iiuidincluding said first and second chambers being arranged so that they `may remain in their struca thermally insulated food storage space provided with an inner liner, thefood storage space being open at the front of the cabinet, a plurality of horizontally disposed walls in said space formingshelves for supporting food articles and the like, one of the 4walls dividing the space into compartments between which circulation of air is substantially prevented, the top, bottomfrear andlateral sides of the liner forming walls of said compartmenta'refrigeration apparatus intural and coolingefiect transmission relationship to said other compartment 'evaporator structure.

.x 14. In a refrigerator including a cabinet having an inner liner forming a storage space provided with' a'front opening, a closure forythe opening, and a solid shelf to divide said space into compartments between which circulation of ing portion in said other compartment,'and concluding evaporator structure in one of the. comchamber adapted to receive matter to be refrigerated, a door for the cabinet opening for inserting and 'removing food products and the like into and 'from said one compartment and also partmenta the evaporator structure having aduit means connecting said heat rejecting portion and said heat abstracting portion, said conduitmeans beingdisposed in said space and passing through the plane of said solidshelf, land said-heat transfer circuit being insertable and removable as a unit into and out of said space through the front opening.

,HUGO M. ULLS'IRAND.

upon removal of they 

